Should you understand everything your child says between the age of 24-30 months?  While your child's understanding is expanding day by day, his/her ability to express his/her self has not quite caught up.  Speech sounds are developing however, not all speech sounds are perfected and you should expect to hear errors.  While your child is developing language skills,  he/she is becoming more independent as well.  Participateing in  pretend play and playing  with other children is a great way to help your child develop communication skills, among other things.  What red flags should you be aware of during this time frame?  Remember Early Intervention is Key.